Fly Casting- How straight is Straight Line Path ?

Making Adjustments on the Fly B.Gammel

a very astute casting student asked me recently, “I think I’m having difficulties keeping a Straight Line Path throughout the stroke. I must be doing something wrong ?”

i love these kind of comments. it shows the person is curious, really pays attention to what they’re doing and shows they’ve studied well. at this point i should say that his loops where ideal, nice and smooth, very close to parallel very nice loops, as nice as what we see Andreas Fismen performing in the 500fps slomo gif below. so, what was the problem then ?
since his casting was spot-on it obviously wasn’t anything he was doing wrong (loops don’t lie. they can’t) but simply his understanding of how rod tip travel should be for a textbook straight line cast but who could blame him ?
diagrams, books, videos and even in real, most instructors explain that just as in the diagram above, SLP (Straight Line Path) is a constant from one end of the stroke to the other. even in Jay and Bill Gammel’s awesome reference construct The Five Essentials of Fly Casting, this straight all-the-way-through concept is very easy to accept and take for granted.

“3. In order to form the most efficient, least air resistant loops, and to direct the energy of a fly cast toward a specific target, the caster must move the rod tip in a straight line.”

but is that what really happens ? lets take a closer look.

'SLP' Borger:Lovoll FC

first published in 2010, these findings aren’t anything new to some of us casting geeks but might be a sorta eye-opener for the non geeks, shedding some light for those who have asked themselves the same question as my student. just as we’ll see in the still below, in this study cast SLP is roughly a little bit more than a third of the overall stroke, most of the rod tip’s path has a mostly domed/convex shape with a somewhat flattened top. *
SLP length Borger:Lovoll

i won’t risk any absolutes but as far as i can tell, the only time we’re going to see a true, all-the-way-through SLP and its resultant tight loop will be when a non-flexible rod (the proverbial broomstick) is used to perform the cast. but even if the broomstick is somewhat frequently brought up in casting-geek circles and is a wonderful tool to understand a lot of casting concepts, it’s not something we use.
our ‘real’ rods bend, react to the forces we apply to them, get shorter as they bend and go back to their original length as they unbend and there’s the caster’s biomechanics and probably a billion other factors that are involved when considering rod tip path and even if they all where within my understanding, they’re not about today’s subject.

to conclude, after having shown this video and image to my student (ah, the beauty of bringing an iPad to lessons!) with a few explanations and demonstrations, you’ll most probably have already guessed it but here was the furthered response to his query.

– knowing this isn’t going to change your life, its just one of those ‘what we thought we where doing isn’t necessarily what was going on’ things.
– does this not-as-straight-as-we-thought SLP change anything in the way we should cast ? nope.
– provided you get the loop shapes you’re wanting to create, should you be doing anything differently ? absolutely not !
– if you want a straight line cast, keep on imagining your complete casting stroke is a straight one (and do all the other elements correctly) and you’ll get that tight loop and a straight line layout.

which in a certain manner, makes it resemble Saint Exupery’s elephant inside a boa drawing a lot more than your everyday ruler. at least in my eyes…
elephant-in-boa-SLP


top image from Bill Gammel’s brilliant Making adjustments on the fly
regiffed video and adjoining image via Grunde Løvoll. click HERE for more of Grunde’s slomo studies on Jason Borger’s site: Fish, Flies & Water
elephant/boa drawing from Antoine de Saint-Exupéry: Le Petit Prince

note- although the loop shape in the gif is textbook ideal, Andreas’ casting stroke seems to be quite long considering he’s only false casting 10m (32.8ft) of line. my guess is he was casting at a fast rate which necessitates a wider casting stroke, perhaps something to do with getting a good visual result with the 500 frames per second camera.